Hi,
some Info on those two file-infectors:
LibertyIcelandyou could try
- to repair avast:
Controlpanel -> software ->avast ->uninstall -> repair
- and do a subsequent boot-time scan
But I doubt it'll help
if possible confirm and/or Clean the infections with online Scanners, e.g. Trend
-> see link "VirusRemoval" below in my sig
or use avast BART-CD
But if this is not a false positive, I'd advise
- (maybe Data-backup via a Clean Boot-Medium) and then
- FDISK
- FORMAT
- proper reinstall with reliable Setup-Media
Scan all your Floppies & other media for infection afterwards